Furnace-arch.



No. 183,778., PATDNTDD PDB. z8, 195.

G. L. DAWSON D D. D. MATHIAS. l

PURNAGE ARCH.

APPLIUATION FILED 00T.2a,1oa.

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3 SHEETS-SHEET 2.

PATBNTBD FEB. 28, 1905. G. L. DAVISON & D. R. MATHIAS.

FURNAGE ARCH No. 783,778. P NTED FEB. 28, 1905. G. L. DAVISON & D. R. MATH FURNAGE ARCH.

APPLIGATION FILED 001126, 1903.

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Patented. February 28. 190% PATnnT fl FFfCE.

GEURGE L. DAVlSON AND DAVID lt. lViATlllhlIAS, OF CHICAGO, ILLINOIS, ASSIGNORS TO PROTECTED FUltN/-iUlC PORT C0., OF ClilCAGG, lLLlu NDIS, A CORPORATlON 0F ILLlhIDlS.

SPECIFICATION forming part of Letters Patent No. 783,778, dated February 28, 1905.

Application filed October 26, 1903. Serial No. 178,657.

lo (tlf/f 'LU/wm it may concern:

Be it known that we, Geenen L. Davison and DAVID R. MATHIAS, both residents of Chicago, in the county of Cook and State of illinois, have invented certain new and useful Ylmprovements in Furnace-Arches, of which the following is a specification.

This invention relates to improvements in furnace-arches, and refers more specifically to a water-cooled arch particularly adapted for use in conjunction with open-hearth furnaces.

The salient object of the invention is to provide a construction which will successfully withstand the intense heat of an open-hearth furnace and which is at the same time of simple and economical construction.

To this end the invention consists in the matters hereinafter described, and more particularly pointed out in the appended claims.

In the drawings, Figure 1 is a horizontal sectional view of an open -hearth furnace, taken on the indirect line 1 l of Fig. 2 and lookingI downwardly. Fig. 2 isa longitudinal sectional view of the furnace, taken on line 2 2 of Fig. 1. Fig. 3 is a cross-sectional View taken on line 3 3 of Fig. 2 and looking in the direction of the arrows. Fig. 4 is another cross-sectional View taken on line 4 4 of Fig.

V1 and looking' in the direction of the arrows.

Referring to the drawings, l designates the main furnace-chamber, provided at each end with inlets, as 2 2, and also with a suitable runner 3, which communicates with the inte rior of the furnace through the bed thereof` as indicated at 4.

5 designates the upper wall or roof of the furnacechamber, which is of refractory material and has the form of a relatively [iat arch, the roof of the chamber being given this form for the purpose of confining the combustion into close proximity with the upper surface of the material treated, but without bringing said upper wall into direct range of the inliowing burning gases.

The opposite ends of the furnace are similar in construction, and in use the direction of cireulation of the gases of combustion through the furnace is reversed at intervals, the inletduct of a given end becoming the outlet duct or flue, and vice versa.

Tith each duct or outer arch 2 is arranged to communicate separate air and gas passages 6 and 7, respectively, the passages 6 and 7 being' arranged to converge and meet at a point within the respective arches 2 a short d istance outside of the main chamber, as shown clearly in Fig. S2. lhat portion of the partitionwall 8 which separates said passages which forms the point of conflux of the two passages constitutes an arch 9, which arch forms the chief feature of the present invention. ',he supplies of gas and air admitted to the furnace through the passages (5 and 7' are highly heated and an intense combustion takes place, the combustion commencing at the point where the two supplies meet and extending' thence throughout the length of the furnace-chamber. .lt will be noted that the upper or air passage 6 is deflected downwardly at its point of conflux with the gas-passage, and the inleading-duct 2 extends in continuation of the air-duct (5, so that the general direction of the inlet is obliquely downwardly toward the center of the furnace-chamber. It is important that the gases of combustion be thus directed downwardly and inwardly in order that they may act more effectively upon the material being' treated and also in order that the roof of the chamber may be protected. Heretofore the point of the arch 9 has been rapidly burned away bythe intense combustion in spite of the use of the most highlyrefractory materials commercially available. As the point of the arch is burned back or shortened it will be obvious that the general direction of the iniiow becomes changed and approaches the horizontal and sometimesin extreme cases is so changed as to be directed upwardly against the roof of the furnacechamber. rl`he alternate reversal of the circulation through the furnace undoubtedly contributes to the rapid burning away of the points of the arches, as above described.

It is the object of the present invention to provide an arch which will withstand the heat l parent.

charge into an outlet-trough 12, the several pipes being arranged to extend entirely through the furnace from side to side and at lower flues leading into one end thereof and their central portions bridging or overlying' the lower or gas ducts?. Theheader ll communicates with any suitable source of watersupply, and in use'sufcient water is circulated through the pipes to maintain the latter cooled below the softening-point, notwithstanding the intense heat to which they are subjected.

It is to be noted that in the preferred construction shown the refractory material of the arch isall arranged above the supporting and protecting tubes l0, or, in other words, the tubes are not embedded within and covered by the refractory material. Vith this construction the arch remains practically intact, notwithstanding the refractory portions thereof may be more or less fractured by the intense heat, and the arch is not eaten away or shortened in use. This is a feature of great importance, since it is found in practice that as soon as the arch has been thus shortened to any considerable extent the direction of the blast change-s and the roof-wall of the furnace is rapidlydestroyed. Another feature of advantage of our construction is that by using the water-tube supports for the refractory material refractory brick may be used composed of material which are more highly refractory than silica brick, but more susceptible of fracturing and crumbling under intense heat-such, for example, as mag'- nesite and chrome bricks.

Still another and very important feature of the present invention resides in the facility with which the arch may be repaired without interrupting the operation of the furnace. The refractory superstructure of the arch will be burned off gradually, especially at its free or exposed edge; but as soon as it is to any substantial extent deformed it may be repaired by simply depositing a small quantity of suitable pulverized or granular refractory material; which will vitrify or burn onto the upper edge of the arch. This material may be passed in through the side doors 13 of the furnace by means of a long-handled paddle or spoon-like tool. The arch may thus be repaired from time to time without interrupting the operation of the furnace, and when it is considered that the preservation of the integrity of the inlet-passages means the preservation of the entire furnace indenitely or at least for a greatly lengthened period the importance of our invention is apiVhile we have herein shown and described a preferred embodiment of our invention, yet 1t will be understood that the invention may be otherwise embodied, and we do not, therefore, limit ourselves to the construction shown except to the extent that the same is made the subject of specific claims.

Ve claim as our invention- 1. In an open-hearth furnace, the combination with the main chamber, of upper and a horizontally and transversely extending' divisional arch separating' said upper and lower iiues at or near their point of entrance to the main chamber, said divisional arch comprising an upper layer of refractory material and an underlying transversely-extending watercooled structure, underlying and directly supporting substantially all parts of the refractory material of those portions of the divisional arch which form the point of coniiux of said Lipper and lower flues.

2. In an open-hearth furnace, the combination with the main chamber and main flue leading' into one end thereof, and downwardly and inwardly inclined in its general direction, of gas and air passages converging and leading into said main flue and a divisional arch at the point of confiux of said passages consisting of a series of underlying water-tubes. a superposed refractory brick structure, and means for circulating water through said tubes, substantially as described.

3. ln an open-hearth furnace, the combination with the main chamber and main flues communicating with the respective ends of said main chamber, of air and gas passages leading into each of said main flues and arranged in super-posed relation to each other, and divisional arches arranged at the respective points of coniiux of the air and gas passages, each divisional arch being formed of an underlying horizontally-disposed, transversely-extending bridging series of closelycontiguous watertubes, and a superposed refractory brick structure, as and for the purpose set forth.

4. In a device of the class described, the combination with the body of a furnace, and an outer arch at each end of the same, of an inner arch having a at lower surface within each of said outer arches and out of contact therewith, passages for conducting gas to one side of said inner arch, and air to the other side thereof, and a plurality of water-pipes lying immediately below the said inner arch and in continuous contact with the lower surface thereof.

In adevice of the class described, the combination with the body of the furnace and an outer arch at each end of the same, of an inner arch within each of said outer arches, and out of Contact therewith, passages for conduct- IOO IIO

ing,r gas on one side of said inner arch and air ou the other side thereof and means for artificially coolingI said arches.

6. ln a device of the class described, the conihination with the body of the furnace and an outer arch at each end of the same, of an inner arch within each of saidouter arches, and out of contact therewith, passages forconductingI gas to one side of said inner arch and air to the other side thereof, and a series of wa 'ter-pipes underneath each of said inner arches, said pipes serving' the double purpose of cooling; said arches and supporting loosened portions thereof.

7. In a device of the class described, the cornbination with the body of the furnace, of snitablc and air ports arranged one above the other at each end of the furnace, said ports being adapted to serve at certain times as inlet-ports, and at other times as exhaust-ports, of a substantially horizontal septum separating said ports, and a series of closely-contiguous w"ate1conducting pipes arranged in contact with and below said septum, said pipes serving the double purpose of cooling the septum and supporting,l any loosened portions thereof.

8. ln a device of the class described, the combination with the body of the furnace, of gas and air ports arranged one above the other at each end of the furnace, such ports serving at certain times as inlet-ports and at other times as exhaust-ports, a horizontal arch separating each pair of said ports, the edge of which is exposed freely to the interior of the furnace and a water-cooled shield below cach of said arches at the edge nearest the center of the furnace, said shields extending1 across the entire width of said inner arches, and serving the double purpose of protecting' the surface thereof from heat, and supporting the same.

GEORGE L. DAVISON. DAVlD R. EVIATHIAS. Witnesses:

ALBERT H. GRAVES, FREDERICK C. GOODWIN. 

